Glow discharge device



April 4, 1939; G. HOLST" 2,152,995

GLOW DISCHARGE DEViCE Filed Feb. 9, 1937 Inverw-tor:

' Gilles Hol t, by fi wyfix/ wzm H i s- Att'orn ey.

Patented Apr. 4,1939

' UNITED STATES 2,152,995 snow nrscnanas nnvron Gilles new, Eindhoven, Netherlands, allignorto General Electric Oompnm-a corporation of New York Application February a, 1m Serial No.

- m the Netherlands February 19. ms

8 Claims. (01. zit-11.4)

It is known toenclose electric discharge tubes having a gas or vapor or combination of gas and vapor filling in 'a container or enclosure which is separate from the discharge tube and is 5 secured to the tube in a removable manner. Sodium-vapor discharge tubes or lamps are, for

instance, used frequently in combination with a double-walled, evacuated container which is placed around the discharge tube in such a way 19 that the container and the tube can easily be removed and so that each can' be transported and interchanged. The container may, for instance, be connected to the discharge tube by means of a screw connection or other form of II connection which can be readily loosened. Furthermore, discharge tubes, such as high-pressure mercury-vapor discharge tubes, are. known which are arranged within a single-walled container and are secured thereto, not permanently, but in such a way that they can be taken apart.

In these constructions, air or other form of deleterious gas or vapor is present between the discharge tube and the container, and the space between the tube and the container is sealed as 25 well as possible in order to separate this space from the surroundings.

The present invention relates to electric dis charge tubes with a gas or vapor filling and which are enclosed in a container secured to the tube in 80 a nonpermanent, removable manner; the invention has the purpose of improving this construction.

According to the invention, a material which attracts water is placed in the closed space be- 86 tween the discharge tube and the container. It hasbeen found that in spite of the fact that this space is substantially closed, under certain conditions of the surroundings, such a large quantity of water vapor can penetrate into this space 40 that the ingition of the discharge tube is madedimcult. Sodium-vapor lamps which were placed in a Dewar vessel ignite without trouble in the case of dry weather, while they do not ignite when the same voltage is applied in foggy 46 weather. By placing a material which attracts water to a high degree in the space between the discharge tube and the container, the increase inthe ignition voltage, caused by the water vapor which,has penetrated into this space, can be so avoided.

It is possible to use the hygroscopic materiala.

. calcium oxide or calcium chloride for absorbing the water but it is preferable to utilize a material which, at the temperature at which it is u heated during the operation of the discharge tube. 88am liberates the absorbed water vapor. The air in the space between the tube and the container is heated during operation and then creates an excess in pressure. As a result, a part of this air with a part of. the water vapor which is again liberated from the material, is forced to the outside through the removable connection. In this case, the material utilized can consist, to advantage, of active carbon or silica gel.

The drawing shows two physical embodiments m according. to the invention.

Figs. 1 and 2 show a discharge tube which is enclosed by a double-walled container, while Fig. 3 shows a discharge tube which is surrounded by a single-walled container.

In Figs. 1 and 2, l is a U-shaped discharge tube which is provided with a gas filling that contains sodium vapor and which is utilized for the emission of light rays. This discharge tube is provided with a base 2 on which the contacts 3 are located. The discharge tube is surrounded by a double-walled container 4 which is evacuated and which is fastened to the ring 5 consisting of insulating material. This 'ring fits the a base 2 as tightly as possible so that the best posg5 sible. seal is obtained of the air-filled space between the tube and the container 4. The ring 5 and the base 2 are secured together by the screw 6. a

In the indicated space, there is located at the so bottom of the. inside wall of the container 4 a tablet or pellet l which consists of highly active carbon and which strongly attracts water vapor. This pellet can b'eplaced on the bottom of the container.

It is apparent that it is also possible to secure the hygroscopic material in such a manner that it cannot move'even when the discharge tube or the container is placed in a different position. For example, it is possible to place this material in a small basket of metal screening and secure this basket to one of the currentsupp wires.

In Fig. 3, 8 shows a high-pressure mercuryvapor discharge tube which, during operation, has a very high mercury-vapor pressure of, for example, atmospheres. The discharge tube is secured to the base ll of insulating material with the aid of the current-supply wires 9 and Ill. The tube is surrounded by a single-walled container l2 to which .the ring It consisting of insulating material is secured. This ring encloses a portion of the base H and is connected thereto by means of the screw it. In the lower 2. In combination, c gcsecus discharge device,

a gaseous pervious container smroundmg said de vice and spaced therefrom means for cbcorbirig water vapor in the space cod for releasing the vapor when heated to operating temperatures said means being positioned between said device and said container to avoid changes in time stcrtinc voltage of said discharge device.

3, In ccmbiiicticm cccscous electric dis-= charge icmzi device a removable and transparent container therefor, and a quantity or carbon in the spcce between the hump devicc and said e tccccc 4. In combination, a gaseous electric lamp device, a remcvcblc container for acid lamp device, and hygroscopic material in thc space kictwccn said lamp device and scid ccn tciner to avoid changes in the starting voltage of said discharge device. v

5. In combination, a gaseous electric discharge iamp device, a; removable container thcrefcr, cod a pellet of a. compound containing calcium pos tioned between the lamp device and the com tamer for absorbing water vapor to cvoid changes in the starting voltage of said discharge device. 1 1

6. In combination, an electric dischcrge dcvicc, c gas pervicus enclosure for said device and means for absorbing deleterious gases iii space between said device and said enclosure to avoidchenges in; the starting voltcceof scid 

